You know, after Man of Steel... I don't know how much sense would Aquaman make into this DCCU.
As Atlantean are not humans but a sort of "secret race", it would be the same "are we alone in the universe?" all over again.
Will they change Aquaman's background? I have no idea. But I think the best idea they could have is giving Atlantis some mystic or magic background, to differentiate it from MoS the most possible.
I also think an Aquaman movie would better be done after the Justice League film, to basically translate Geoff John's take on the character to the big screen.